Refrigerating apparatus



REFRIGERATING APPARATUS Filed Oct. 5', 1954 INVENTOR. Lamas/ms l2P/l/L/PP ATTO NEY.

Patented June 7, 1938 UNITED STATES 2,120,185 REFRIGERATING APPARATUSLawrence A. Phillpp, Detroit, Mich.', assignor, by

mesne assignments, to Nash-Kelvinator Corporation, Detroit, Mich., acorporation of Maryland Application October 3, 1934, Serial No. 746,682

3 Claims.

The present invention relates to refrigerating systemsand particularlyto refrigerating system known as the multiple system in which aplurality of evaporators are connected with a single com- 5pressorcondenser unit.

One of the objects of the present invention is to provide arefrigerating system employing a plurality of evaporators and a singlecompressor condenser unit and employing mechanism for preventing theflow of refrigerant through one of the evaporators when the temperatureof the medium cooled thereby is reduced to a desired predeterminedminimum and employing mechanism which prevents the flow of refrigerantthrough another of the evaporators until gaseous refrigerant is nolonger withdrawn from theflrst mentioned evaporator.

In carrying out this object it is a further object of the presentinvention to adjust the expansion valve of the colder or coldest of aplurality of evaporators in such a manner that it will not A admitvaporizable refrigerant to its evaporator until refrigeration by thewarmer evaporator or evaporators is completed.

Further objects and advantages will be apparent from the followingdescription, reference being had to the accompanying drawing wherein apreferred form of embodiment of the present invention is clearly shown.The drawing is a diagrammatic view of improved refrigerating system.

For the purpose of illustrating one form of the invention, I haveprovided two refrigerator cabinets, 26 and 2 I. The cabinet 20 is hereinshown as an ice cream cabinet and the cabinet 2| as a water cooler.Brine is contained in the cabinet 20 and surrounds the ice cream cansleeves 23. The cabinet 21 contains water which is used as a heatexchange medium for conducting heat from the circulating water in watercoil 24. v An evaporator 26 is immersed in the brine in cabinet 20 andan evaporator 21 is immersed in the water in cabinet 2 I. A compressor36 is utilized for withdrawin gaseous refrigerant from evaporators 26and 21. This gaseous refrigerant is conducted from evaporator 26 by apipe 31 and a pipe 32. Gaseous refrigerant is conducted from evaporator21 through a pipe 33, valve 34, pipe 35 and pipe 32. The refrigerantafter being compressed by the compressor 30 is conducted to a condenser31 wherein it is cooled and liquefied and then drains to a receiver 38.The liquefied refrigerant is conducted from the receiver 38 through apipe 39 and an expansion valve 40 into the evaporator 21. The liquefiedrefrigerant is conducted from the receiver.38 through pipes 39 and 42and'an expansion valve 43 to the evaporator26. The expansion valve 40may be of any suitable type and is herein shown as the pressure typewhich the is well known in the art. This type of valve tends to maintaina constant pressure within the evaporator, that is it opens when thepressure within the evaporator is reduced to a predetermined minimum bythe compressor and increases and decreases the flow of refrigerant tothe evaporator as the press e decreases and increases respectively inthe e aporator. One form of such expansion valve is shown in the patentto Slagel 1,742,323.

The flow of gaseous refrigerant from evaporator 21 is controlled by ashut off valve 34 and this valve is actuated by a pressure system. Thevalve includes a metallic bellows 45 inclosed in a casing 36. Thebellows 45 is arranged to raise and lower the valve proper 46. When thepressure in the casing 36 is increased, the bellows 46 will collapse toclose the valve 46 on its seat. The casing 36 is connected by a tube 41with a bulb 48. The bulb 48 contains a freezing solution such as waterand a quantity of oil is placed within the casing 36 and tube 41.

The operation of the compressor causes the water adjacent the evaporator21 to freeze and the bulb 48 is disposed within the cabinet in such aposition that the water therein will freeze vbefore the water adjacentthe coil 24 freezes. When the water in bulb 48 freezes and consequentlyexpands, it will cause the oil in tube 41 and casing 36 to force thevalve 46 downwardly and thereby positively shut off the flow of gaseousrefrigerant from evaporator 21.

The expansion valve 43- is also the pressure operated type but it isadjusted so that it will not operate until a relatively low pressure isattained in evaporator 26. In fact no liquid refrigerant will passtherethrough as long as the valve' 46 is open. After the valve 46 isclosed and the compressor 30 is functioning'to reduce the pressure onthe low side of the refrigerating system, the pressure within theevaporator 26- will be decreased sufliciently to open the valve 43substanw tially immediately and thereafter the valve 43 tendsto'maintain a constant low pressure within the evaporator 26. r

From the foregoing it is apparent that I have provided a multiplerefrigerating system in which the compressor-condenser unit need be ofsuch size only for efficient cooling of the evaporator having thelargest demand for refrigeration. The compressor condenser unit isconnected first to one of the evaporators and satisfies the demand ofthat evaporator and, after that demand issatisfied, it is then connectedto the other evaporator. For example if there is a demand forrefrigeration by the water-cooler, valve 46 will be opened and thecompressor-will withdraw the gaseous refrigerant from evaporator 21only. At this time the gas generated is suflicient to demand the fullattention of compressor 36. Afterthe demand is satisfied, the valve 46closes the outlet of evaporator 21 and then the pressure within the lowpressure side of the system will be reduced sufilciently to open thevalve 46 and cause refrigeration within the evaporator 26. Under certainconditions there may be a simultaneous demand for refrigeration byevaporators 26 and 2 1. However under this condition the evaporator 21is first satisfied and at no time is there a demand on the compressorfor refrigerating both evaporators simultaneously. Although the valve 46is closed and the refrigerating system is operating to cool evaporator26 and then there is a demand for refrigeration by evaporator 21, thevalve 46 will open and due to the fact that the pressure withinevaporator 21 is higher than the pressure within evaporator 26, theopening of the valve 46 will cause an increase in pressure in evaporator26 to close the valve 48. When the valve 43 is closed, the work done bythe compressor is concentrated upon evaporator 21 and will remain inthat state until the refrigeration demand is satisfied by evaporator 21at which timezthe valve 46 will close and refrigeration will then beresumed on evaporator 26.

In order to maintain desired temperatures, the compressor isintermittently operated. Compressor 30 is driven by a motor 60 and themotor is started and stopped by a snap acting controller 6|. The circuitto the motor includes wire 62, controller 6|, wire 62, motor 66 and wire64. This controller is operated to open and close the motor circuitindividually either by the temperature prevailing in cabinet 20 or thetemperature prevailing in cabinet 2| and likewise conJointly operated bythe temperature prevailing in both cabinets. For this purpose there isprovided a thermostat 66 incabinet 20 and a thermostat 61 in cabinet 2I. Two pressure operated bellows 68 and 66 are included in thecontroller. Either of these bellows is arranged to actuate thecontroller for starting and stopping the motor 66. A pressure tube 60connects thermostat bulb 66 with bellows 68 and a pressure tube6|connects thermostat bulb 61 with bellows 66. If there is a demand forrefrigeration in cabinet 20, a volatile fluid in bellows 66 will expandand cause the bellows 68 to close the motor circuit. If there is nodemand for refrigeration by evaporator 21, then the thermostatic system66, 66 and 68, will break the motor circuit when the refrigerationdemand in cabinet 26 is satisfied. Likewise, if there is a demand forrefrigeration by cabinet 2|, the thermostatic system containing volatilefluid including bulb 61, tube 6| and bellows 69 will cause thecontroller to complete the motor circuit and if thereis no demandfonnafrigeration by cabinet 20, after the demand for refrigeration incabinet 2| is satisfied, the thermostatic system 61, 6| and 66 willoperate to interrupt the motor circuit. However, as previouslyexplained, if there is a demand for refrigeration after completion orsatisfying the demand of cabinet 2|, the motor will remain operativeuntil the refrigeration demand in cabinet 26 is satisfied. Thethermostatic system 61, 6| and 68 is adjusted so that it will notactuate the controller to complete the motor circuit until after-thevalve 46 is open and it will interrupt the motor circuit, when there isno demand for refrigeration by cabinet 26, Just prior to the closing ofvalve 46.

While the form of embodiment of the present invention as hereindescribed constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow:

I claim as my invention:

1. A refrigerating system comprising in combination, a plurality ofevaporators each having an inlet for liquid refrigerant and an outletfor gaseous refrigerant, means for withdrawing gaseous refrigerant fromthe evaporators and for condensing the same and for conducting thecondensed refrigerant to the evaporators, means at the outlet end of oneof said evaporators for interrupting the fiow of refrigerant throughsaid evaporator after the medium cooled thereby is reduced to apredetermined temperature, the operation of the interrupting meanscausing said first means to direct its withdrawing action primarily tothe other evaporator to decrease the refrigerant pressure therein tobelow the pressure in the first evaporator substantially immediatelyafter the second means is rendered effective, and means responsive tosaid reduced pressure in said other evaporator forstarting the flow ofrefrigerant through the said other evaporator.

2. A refrigerating system comprising in com- I bination, a plurality ofevaporators each having an inlet for liquid refrigerant and an outletfor gaseous refrigerant, means for withdrawing gase ous refrigerant fromthe evaporators and for condensing the same and for conducting thecondensed refrigerant to the evaporators, means at the outlet end of oneof said evaporators for interrupting the fiow of refrigerant throughsaid evaporator after the medium cooled thereby is reduced to apredetermined temperature, the operationof the interrupting meanscausing said first means to direct its withdrawing action primarily tothe other evaporator to decrease the refrigerant pressure therein tobelow the pressure in the first evaporator substantially immediatelyafter the second means is rendered effective, and an expansion valveresponsive to said pressure within the said other evaporator operable toadmit refrigerant from the first means only in response to said reducedpressure.

- 3. A refrigerating system comprising in coman inlet for liquidrefrigerant and an outlet for gaseous refrigerant, means for withdrawinggaseous refrigerant from the evaporators and for condensing the same andfor conducting the condensed refrigerant to theevaporators, means at theoutlet end of one of said evaporators for inbination, a plurality ofevaporators each having terrupting the fiow of refrigerant through saidrefrigerant pressure therein to below the pressure in the firstevaporator substantially immediately after the second means is renderedeffective, means responsive to said reduced pressure in said otherevaporator for starting the-fiow of refrigerant-through the said otherevaporator and means affected by the temperature of either of saidevaporators for controlling the first mentioned means. p

' LAWRENCE A. PHILIPP.

